Battery saving techniques for portable communication receivers are well known. Battery life has become so important in radio pagers that entirely new signaling protocols have been developed with battery life extension a primary motivation. One new signaling protocol is a synchronous protocol comprising a sync block having a first bit and frame sync transmitted at a predetermined baud rate, followed by a second bit and frame sync transmitted at a second baud rate. The second baud rate may be either the same as the first baud rate, or a different (higher) baud rate. The first bit and frame sync defines the second baud rate. Both the first and second bit and frame syncs comprise redundant first and second portions to provide greater reception reliability in weak signal environments.
Current pagers operating on the new signaling protocol monitor and synchronize with the entire first bit and frame sync at the predetermined baud rate. The pagers then monitor and synchronize with the entire second bit and frame sync at the second baud rate. Under some conditions, such monitoring of the first and second bit and frame syncs in their entirety is required for proper operation of the pager. Under certain other conditions, however, such complete monitoring of the syncs is not necessary for proper operation of the pager, and is wasteful of battery life.
Thus, what is needed is a method and apparatus that can determine dynamically whether complete monitoring of the sync block is required, and that can perform accordingly in order to save battery power.